1. Field of the Invention
The present invention relates to a method and an apparatus for an ultrasonic wave medical treatment such as a shock wave treatment in which a treatment target such as a cancer tissue or calculus in a patient is destroyed by utilizing a concentrated energy of ultrasonic shock waves, or an ultrasonic thermal treatment in which a treatment target such as a cancer tissue is destroyed by using a thermal effect of continuous ultrasonic waves.
2. Description of the Background Art
Recent progress have been made on a shock wave medical treatment apparatus for destroying a treatment target such as a cancer tissue or calculus in a patient by utilizing a concentrated energy of ultrasonic shock waves.
An example of a recently developed shock wave medical treatment apparatus is disclosed in Japanese Patent Application No. 62-290158 (1987) by the present inventor, which will now be described with reference to FIG. 1.
This shock wave medical treatment apparatus of FIG. 1 comprises: a shock wave applicator 17 including a shock wave transducer 15 for transmitting ultrasonic shock waves, and an ultrasonic wave transducer 16 for transmitting imaging ultrasonic waves to carry out a B mode scanning (tomographic imaging) and receiving echo signals resulting from the B mode scanning; a pulser 18 for providing pulse signals to drive the shock wave transducer 15; a transmitter and receiver circuit 19 for providing pulse signals to drive the ultrasonic wave transducer 16, and collecting the echo signals received by the ultrasonic wave transducer 16; a signal processor circuit 20 for converting the echo signals collected by the transmitter and receiver circuit 19 into video signals by applying the amplitude detected; a signal converter circuit 21, such as a digital scan converter, for performing signal conversion on the video signals obtained from the signal processor circuit 20; a CPU 22 for controlling the operation of each element of the apparatus; a timing controller 23 for controlling the process timing of the pulser 18 and the transmitter and receiver circuit 19; a display unit 27 for displaying a fan shaped acoustic region 42 imaged by the ultrasonic wave transducer 16 and images of the body surface, organ or calculus along with a focal point marker 26 indicating a focal point of the ultrasonic shock wave transmitted by the shock wave transducer 15; a pulse generation switch 29 connected to the CPU 22 for setting the timings for generating the pulse signals to be given from the pulser 18 to the shock wave transducer 15; and a position controller 30 for adjusting the relative position of the shock wave transducer 15 and the ultrasonic wave transducer 16.
Referring now to FIG. 2, details of the shock wave applicator 17 will be described.
This shock wave applicator 17 comprises: the shock wave transducer 15 for transmitting the ultrasonic shock waves focused to a focal point 41a located inside a patient 32; a water bag 33 containing water which is provided on a shock wave transmitting side 15a of the shock wave transducer 15 and which functions as an acoustic coupler; and the ultrasonic wave transducer 16 for transmitting the imaging ultrasonic waves to carry out the B mode scanning and receiving echo signals resulting from the B mode scanning at a transmitting and receiving surface 16a, which is located within a shock wave region 41 between the shock wave transmitting side 15a of the shock wave transducer 15 and the focal point 41a of the ultrasonic shock wave, and which forms the acoustic field 42 including the focal point 41a.
In further detail, the shock wave transducer 15 has a concave oscillator (not shown) of a constant curvature, and at a center of this shock wave transducer 15 the ultrasonic wave transducer 16 is attached through a supporting and driving unit 36 which support the ultrasonic wave transducer 16 with respect to the shock wave transducer 15, and changes the relative position of the ultrasonic wave transducer 16 in a direction of the arrow B with respect to the shock wave transducer 15, according to the control signals from the position controller 30. This can be furnished for example by providing a rack member on a side of the ultrasonic transducer 16 and a pinion gear connected to a motor in the supporting and driving unit 36, where a rotation angle of the motor is controlled according to the control signals from the position controller 30 (FIG. 10)
The water bag 33 located on the shock wave transmitting side 15a of the shock wave transducer 15 has an approximately cylindrical shape with a bottom surface of approximately the same radius as the shock wave transducer 15, formed by a side bellows 33 which can be extended or contracted within a prescribed angle range from the direction of the arrow B and a bottom side 37 made of a thin film having approximately the same acoustic impedance as the water.
In this shock wave medical treatment apparatus, a renal calculus 39 in a kidney 38 of the patient 32 can be treated as follows.
First, the shock wave applicator 17 is positioned over the patient 32 such that the bottom side 37 of the water bag 33 makes a contact with a surface 32S of the patient over the kidney 38. Then, by using the ultrasonic wave transducer 16, the tomographic image of the patient 32 is obtained on the display unit 27. Here, the transmitting and receiving surface 16a of the ultrasonic wave transducer 16 also makes a contact with the surface 32S, so that a clear tomographic image unaffected by the bottom side 37 of the water bag 33 and the water can be obtained.
Next, when the image of the kidney 38 is obtained on the display unit 27, the renal calculus 39 is searched on the display unit 27. Here, the display unit 27 also displays the shock wave region 41 and the focal point marker 26, and the display unit 27 displays the real-time image which changes as the shock wave applicator 17 is moved. When the renal calculus 39 is found on the display unit 27, the shock wave applicator 17 is adjusted carefully to place the focal point marker 26 on the image of the renal calculus 39. When the focal point marker 26 is placed on the image of the renal calculus 39, the shock wave applicator 17 is fixed at that position.
Next, the operator operates the pulse generation switch 29 to provide the control signal to the pulser 18 through the CPU 22 and the timing controller 23. In response, the pulser 18 provides the pulse signals to the shock wave transducer 15 and the shock wave transducer 15 transmits the ultrasonic shock waves focused toward the renal calculus 39 located at the position of the focal point marker 26 which subsequently destroy the renal calculus 39 by their concentrated energy.
The similar procedure is repeated until the entire renal calculus 39 is completely destroyed.
In a case of an ultrasonic thermal treatment apparatus, the apparatus has a configuration similar to the shock wave medical treatment apparatus described above, except that the pulser 18 provides continuous oscillation signals such that the shock wave transducer 15 transmits continuous ultrasonic waves instead of the ultrasonic shock waves, which destroy the treatment target by using a thermal effect of the continuous ultrasonic waves.
Now, in such a conventional ultrasonic wave medical treatment apparatus, it is generally considered preferable to carry out the treatment process while checking the effect of the treatment several times in a course of its progress because it is rather usual for the treatment target as well as the patient to be moving around during the treatment process due to the breathing by the patient or other causes.
However, in a conventional ultrasonic wave medical treatment apparatus, the treatment process is set out completely at the beginning and carried out altogether at once as set out in advance, so that it has been difficult to check the effect of the treatment in the course of progress in the treatment. This implies that efficient treatment may not be carried out depending on the setting at the beginning. On the other hand, when the entire treatment process is divided into several sections and each section is carried out separately, it is necessary in a conventional ultrasonic medical treatment apparatus to make a setting at a beginning of each section, so that the treatment process can be executed efficiently.